Goldbeater lubrication material



entedJuly 18,1944.v

' My present invention relates to the goldbeaters Patents Dec. 25, 1945STATES ra'rlazu'l" oFFlcs 2,391,653 connnusraa LUBRICATION MATERIALDonald 1). Swift, Hartford, Conn., assignor to M. Swii't & Sons, lnc., acorporation, of Connecticut No Drawing. Original application October 28,1939, Serial No. 301,797, now Patent No.

r 2,354,072, dated July 18, 1944. Divided and this application July 18,1944, Serial No. 545,539

2 canine (cl. ess-42.1)

- This application is a division ofapplication Serial No. 301,797, fliedOctober 28, 1939, Goldbeating lubricant, now Patent No. 2,354,072, pat;-

" ess is continued until the leaf has reached the desired size andthinness.

The conventional goldbeaters skins are of ani-- mal origin, butsubstitutes such as Cellophane or cellulose acetate may be used. Tofacilitate the beating operation, it is customary to doctor theoldbeater's skin or the substitute and toadd a suitable lubricant. Theconventional doctorin long used for this purpose consists essentially ofisinglass, gum arabic, shellac, and spices such as safiron, cinnamon,and cloves in red wine; The lubricant is usually made up from soap,gypsum, and water. or in some instances, alcohol.

I have found that a greatly improved goldbeaters lubricant is obtainedby the useof a mineral carrier which is soft enough to be scratched by afingernail and which can be subdivided to almost microscopic dimensions.I have found ,that the lmbedding of such a mineral carrier in a fattyacid sodium salt produces a far superior lubricant. Y I

To this end, I prepare the lubricant of the present invention bydissolving a fatty acid sodium salt such as sodium stearate or sodiumpalmitate in a suitable alcohol such s prOPYil alcohol: suitable'orsanicsoaps may be used in place of the sodium stearate or palmitate. Thedesired characteristics of the salt are that it be soluble in alpowderform,'-is then mixed into the solution; an alkaline earth soap, such ascalcium, magnesium I or zinc stearate, may be used instead of thecalclumsulphate. It is preferred that a uniform mixture be obtained sothat the fine particles of the dehydrated calcium sulphate powder orsoap are suspended in the solution of the sodium stearate or sodiumpalmitate in alcohol, the alcohol tending to inhibit hydrolysis of thesoap. The alcohol is then evaporated by any suitable, wellknown methodand the residue is a smooth, finegrained lubricant far superior to anythat have heretofore been used.

It is preferred to use such proportions of the sodium stearate or sodiumpalmitate and the completely dehydrated calcium sulphate that the finalproduct comprises particles of calcium sulphate each covered with asurface layer of soap. For example, 6 /2 oz. of sodium stearate aredissolved in about 3 qts. of alcohol. After the soap is completelydissolved, 12 lbs. of completely dehydrated calcium sulphate in a finelypowdered form are slowly stirred into the solution. The

alcohol is then evaporated.

Theresultant lubricant is fine grained, soft,

will not scratch or puncture the gold or other metallic leaf during thebeating operation and has very superior lubricating qualities.

While I have described a specific mineral carso rier and specific soaps,it is obvious that other cohol, non-adhesive, with a fairly high meltin4 c rrie s and other soaps or their equivalents may be used in varyingproportions, without departing from the spirit and the scope of theinvention as defined in the appended claims.

Iclaim:

l. The method of preparing a lubricant for metal beating, comprising thesteps of dissolving sodium palmitate in alcohol, mixing completelydehydrated calcium sulphate uniformly therein to obtain a suspension ofthe calcium sulphate in the solution of sodium palmitate. andevapcrating the alcohol.

2. An improved lubricant for'metal beating comprising comminutedparticles of dehydrated calcium sulphate, each particle being covered bya urface layer of sodium palmitate.

DONALD D. SWIFT.

